You can download the Madhyama guide from the official website of the State Sanskrit Education Board or the board that conducts the Madhyama exam in your state. If it's for Bihar or UP, try checking the official site of the Bihar Sanskrit Shiksha Board or Uttar Pradesh Sanskrit Sansthan. Some guides might also be available on educational websites or local book portals. Also, try searching Madhyama guide PDF download with your state name on Google it might help you find the exact link.